The present invention relates to a signalling device and, more particularly, to a small, portable, lightweight, water-resistant, manually-actuated signalling device having design features for minimizing false or accidental operation.
There are many applications in which it is desirable to employ a signalling device, such as a manually-actuated rf transmitter, which is small, portable, lightweight, water-resistant and not readily susceptible to accidental or unintentional operation. Most commercially-available signalling devices typically employ an on/off actuating switch which is either a raised switch, for example, in the manner of an on/off switch for a paging device or electronic calculator, or recessed within a cavity or depression to prevent accidental or unintentional actuation by virtue of contact with other surfaces. Another type of signalling device, typically carried on the person of the user (e.g., in a pendant form), employs an actuating assembly disposed within a soft, flexible container or bag. The device is enabled by squeezing or compressing the container in prescribed regions whereby the internally-disposed actuating assembly is placed in its "on" position. A device of this type is described in U.S. Pat. No. 4,121,160.
In the case of signalling devices employing raised on/off switches, these devices are susceptible to being accidentally or unintentionally actuated by virtue of the switches being accidentally or unintentionally placed in their "on" positions. In addition, if these signalling devices employ batteries the batteries are susceptible to being undesirably discharged thereby rendering the signalling devices unusable. Further, these signalling devices are not water resistant since liquids can seep into interior areas via small openings around the on/off switches. Signalling devices employing recessed on/off switches are similarly not water resistant. In the case of signalling devices of the squeeze or compressible type, these devices are susceptible to possible false or unintentional operation by virtue of a user or other person unintentionally or accidentally compressing the device against a hard surface, for example, by bumping, sitting or rolling onto the device. In addition, it may be difficult in certain situations for a user of the device to readily locate the regions of the container to be squeezed, for example, if the device is required to be actuated in the dark or by a blind person. Further, the squeezing operation may be difficult to accomplish by persons whose hands are adversely affected by arthritis or some other affliction.